Linked Life Data

6130090

Source:http://linkedlifedata.com/resource/pubmed/id/6130090

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1983-3-11
pubmed:abstractText
In this work we show that intact aminoacyl-tRNA (aa-tRNA) and its 3' half-molecule, but not its 3' C-C-A-aa fragment, require selective ionic conditions for stimulating the mRNA-independent GTPase of elongation factor Tu (EF-Tu) in the presence of ribosomes.l Stimulation by aa-tRNA and its 3' half-molecule is only observed at 20 and 30 mM Mg2+ and not at 10 mM, where they exert inhibitory activity; by contrast, C-C-A-aa enhances the GTPase activity at all three of these Mg2+ concentrations. Ammonium ion is needed for stimulation by C-C-A-aa, whereas it inhibits the stimulation by aa-tRNA and its 3' half-molecule. The concentration of aminoacylated fragments needed for half-maximum stimulation follows this order: A-Val much greater than C-A-Val greater than C-C-A-Val much greater than 3' Val-tRNA1Val half-molecule greater than Val-tRNA1Val. The extent of maximum stimulation of the EF-Tu GTPase in the presence of ribosomes varies moderately depending on the aa-tRNA species; a clear dependence on the nature of the aminoacyl side chain is observed in the effects of their respective C-C-A-aa fragments tested (C-C-A-Arg, C-C-A-Val, C-C-A-Phe, C-C-A-Met, C-C-A-Lys). In the absence of ribosomes and at low [Mg2+], the one-round GTP hydrolysis by EF-Tu is enhanced by C-C-A-aa fragments, whereas it is inhibited by the corresponding aa-tRNAs. Our results suggest that besides the 3' aminoacylated extremity another region(s) of the aa-tRNA molecule controls the GTPase of EF-Tu. The "unspecific" stimulation by C-C-A-aa and the "specific," aa-tRNA-like effect of the 3' aa-tRNA half-molecule point to the importance of the T chi C loop and stem, as well as of the adjacent regions for the regulation of this function.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
258
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
995-1000
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Different regions of aminoacyl-tRNA regulate the function of elongation factor Tu.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't